熔体结构与酸性熔岩的某些特征

在流纹质岩浆中,存在两种不混溶的熔体,一种熔体富SiO_2贫FeO,另一种则相反。从熔体结构的角度看,前一种熔体富桥氧,后者则富自由氧。水的解聚作用可以改变流纹质岩浆的结构,即降低它的聚合程度,因此,含水流纹岩浆的粘度低于玄武岩浆的粘度,从而使流纹岩中流纹构造发育。 实际工作中应避免混淆流纹岩与酸性熔结凝灰岩。

The Melt Structure and Some Characteristics of Acidic Lava

The rhyolitic magma includes two immiscible melts, of which one is more enriched in SiO2 ana depletea in FeO, By contrary, the other is enriched in Fe0 and depleted in Si02. In the view of the melt structure, the former is enricheh in bridging oxygen, and the later--in free oxygen. The depolymeriza- tion of water may lead to changing the melt structure of rhyolitic magma, i, e. lowering its polymerizing degree. Therfore, the viscosity of water-bearing rhy- olitic magma is lawer than that of basalt magma and thus the flow structure is generally well developed in the rhyolite. So that it should avoide mixing the difference between rhyolites and acidic ignimbrite on research work.